Several anecdotal reports appear in the literature and newspaper headlines noting the involvement of drivers with diabetes in serious or fatal motor vehicle accidents. Studies of the motor vehicle crash risk of drivers with diabetes are conflicting, with several suggesting an increased crash risk for these operators. Reasons for the increased risk have not been adequately addressed in existing reports. The following study will provide an extensive investigation into the motor vehicle crash risks associated with persons with Type 1 diabetes. It will first examine if differences exist in the frequency of automobile crashes in a population-based sample of diabetic cases and a group of gender and age-matched, non-diabetic controls. Second, it will address the relative contributions of diabetes management practices, hypoglycemia, and late-stage complications as risk factors for automobile crashes. Third, it will outline evidence-based strategies for managing the risks identified in these diabetic drivers. This investigation will be based upon a survey of participants in the Children's Hospital of Pittsburgh IDDM Registry and Allegheny County IDDM Registry, as well as a review of data previously collected in two large studies; the Epidemiology of Diabetes Complications Study, and the DCCT Study. Both studies have collected extensive information on diabetes treatment factors, hypoglycemia, diabetes complications, and motor vehicle accidents. Data collection and analysis will consider the contribution of several human, vehicle, and environmental factors in the crashes identified. Taken together, all 4 data sources provide a unique outlet for identifying and outlining the crash risks for drivers with diabetes. With this information, it will be possible to expand our scientific understanding of the role of diabetes in accidents and outline strategies to minimize its impact. This work has the potential to both enhance employment opportunities for persons with diabetes and maximize safety at existing venues.